Researchers tested the LED deterrents using a silhouette of a seal. Photo: Current Biology
The latest shark deterrent technology may be the humble LED light. In a study recently published in the journal Current Biology, Australian researchers found that LED lighting affixed to the underside of a surfboard might be able to impede a shark’s ability to see its silhouette.
To conduct the study, researchers from Sydney’s Macquarie University traveled to Mossel Bay, South Africa. By towing a seal-shaped decoy behind a boat, they were able to test the deterrent capabilities of various configurations of LED lights attached to its underside.
Photo: Current Biology
“What we found out is that if we put lights on the bottom of the decoys, the sharks leave them alone,” said Nathan Hart, study co-author and head of Macquarie University’s School of Natural Sciences. ”We think this tells us a lot about how sharks see the world, how they detect and target their prey. It also potentially gives us an insight into how we can develop a non-lethal shark deterrent, especially for surfers.”
The lights echo a natural phenomenon called counterillumination, where marine animals (especially those that live in mid-water) emit light on the underside of their bodies in order to break up their silhouette to a predator looking up at them from below.
However, not just any lights worked. Horizontal stripes that were brighter than the background were able to deter sharks, but longitudinal stripes or strobe lights were not effective. As the study’s lead author, Dr. Laura Ryan, told The Guardian, the key was to disrupt the shark’s ability to make out the decoy’s silhouette. “When you do horizontal stripes, the silhouette [appears] wider than it is long, so it’s less like a seal,” she explained.
Though the finding shows promise for potentially developing light-based shark deterrent technologies, there are still some hurdles to overcome. One of those problems is how exactly to power a series of bright lights attached to the bottom of a surfboard while still keeping it ridable. It’s a dilemma that, as a surfer herself, Ryan is all too aware of. “Surfers can be a little bit fussy with their surfboards,” she told The Guardian. “As a surfer, I want it to be usable.”
